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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 11 |
| 5 | 55 |
| 6 | 319 |
| 7 | 2233 |
| 8 | 17641 |
| 9 | 158769 |
| 10 | 1578667 |
| 11 | 17365337 |
| 12 | 207865289 |
| 13 | 2702248757 |
| 14 | 37786779669 |
| 15 | 566801695035 |
| 16 | 9063808803203 |
| 17 | 154084749654451 |
[1,1,1,3,11,55,319,2233,17641,158769,1578667, 17365337,207865289,2702248757,37786779669, 566801695035,9063808803203,154084749654451] |